This invention relates to a radio wave absorber which is widely used for shipping, airplanes, etc. and, more particularly, it relates to a composition of a radio wave absorber of a single layer type which is applied or placed on a reflector made of metal or the like.
In recent years, studies for utilization of radio wave of a microwave range and a millimetric wave range have been briskly carried out in various fields and, as a result, radio wave absorbers for prevention of electromagnetic interference have been receiving public attention.
Among them, wavelength of radio wave of a millimetric wave range is particularly as very short as about 1-10 mm and, therefore, in the so-called xe2x80x9cabsorption of matching typexe2x80x9d where radio wave is absorbed by an absorber placed on the surface of a reflector, there has been a requirement that thickness of the radio wave absorber matching such radio wave is to be made 1 mm or less.
Further, there has been a dilemma in the radio wave absorber compositions up to now that the radio wave absorber having a thickness of some extent is necessary when the radio wave absorbing property for a broad range of radio wave is to be achieved while, when thickness of the radio wave absorber is to be made thin, radio wave absorbing property for a broad range is not available.
An object of this invention is to provide a composition of a radio wave absorber which is able to efficiently absorb the radio wave of a broad range in spite of the fact that it is a radio wave absorber having a thin thickness.
A gist of the radio wave absorber composition of this invention is that an electroconductive titanium oxide is compounded with a substrate for achieving the above-mentioned object.
It is preferred that the compounding ratio of the above-mentioned electroconductive titanium oxide to 100 parts by weight of the substrate is 5-40 parts by weight and it is also preferred that an electroconductive carbon black is compounded in an amount of from more than 0 part by weight to not more than 4 parts by weight to 100 parts by weight of the substrate.
The radio wave absorber composition of this invention is constituted as mentioned above and, when it is applied or placed on a reflector made of metal or the like, it is possible that a radio wave absorber corresponding to any frequency of a microwave range and a millimetric wave range is prepared depending upon the changes in its thickness and it is also possible that radio wave of a broad range can be efficiently absorbed in spite of the radio wave absorber having a thin thickness.